[3.9] bpo-40826: Fix GIL usage in PyOS_Readline() (GH-20613)
* bpo-40826: Fix GIL usage in PyOS_Readline() (GH-20579)
Fix GIL usage in PyOS_Readline(): lock the GIL to set an exception.
Pass tstate to my_fgets() and _PyOS_WindowsConsoleReadline(). Cleanup
these functions.
(cherry picked from commit c353764fd564e401cf47a5d9efab18c72c60014e)
* bpo-40826: Add _PyOS_InterruptOccurred(tstate) function (GH-20599)
my_fgets() now calls _PyOS_InterruptOccurred(tstate) to check for
pending signals, rather calling PyOS_InterruptOccurred().
my_fgets() is called with the GIL released, whereas
PyOS_InterruptOccurred() must be called with the GIL held.
test_repl: use text=True and avoid SuppressCrashReport in
test_multiline_string_parsing().
Fix my_fgets() on Windows: fgets(fp) does crash if fileno(fp) is closed.
(cherry picked from commit fa7ab6aa0f9a4f695e5525db5a113cd21fa93787)
diff --git a/Parser/myreadline.c b/Parser/myreadline.c
index 04c2793..2dd3623 100644
--- a/Parser/myreadline.c
+++ b/Parser/myreadline.c
@@ -24,25 +24,36 @@
int (*PyOS_InputHook)(void) = NULL;
/* This function restarts a fgets() after an EINTR error occurred
- except if PyOS_InterruptOccurred() returns true. */
+ except if _PyOS_InterruptOccurred() returns true. */
static int
-my_fgets(char *buf, int len, FILE *fp)
+my_fgets(PyThreadState* tstate, char *buf, int len, FILE *fp)
{
#ifdef MS_WINDOWS
- HANDLE hInterruptEvent;
+ HANDLE handle;
+ _Py_BEGIN_SUPPRESS_IPH
+ handle = (HANDLE)_get_osfhandle(fileno(fp));
+ _Py_END_SUPPRESS_IPH
+
+ /* bpo-40826: fgets(fp) does crash if fileno(fp) is closed */
+ if (handle == INVALID_HANDLE_VALUE) {
+ return -1; /* EOF */
+ }
#endif
- char *p;
- int err;
+
while (1) {
- if (PyOS_InputHook != NULL)
+ if (PyOS_InputHook != NULL) {
(void)(PyOS_InputHook)();
+ }
+
errno = 0;
clearerr(fp);
- p = fgets(buf, len, fp);
- if (p != NULL)
+ char *p = fgets(buf, len, fp);
+ if (p != NULL) {
return 0; /* No error */
- err = errno;
+ }
+ int err = errno;
+
#ifdef MS_WINDOWS
/* Ctrl-C anywhere on the line or Ctrl-Z if the only character
on a line will set ERROR_OPERATION_ABORTED. Under normal
@@ -58,7 +69,7 @@
through to check for EOF.
*/
if (GetLastError()==ERROR_OPERATION_ABORTED) {
- hInterruptEvent = _PyOS_SigintEvent();
+ HANDLE hInterruptEvent = _PyOS_SigintEvent();
switch (WaitForSingleObjectEx(hInterruptEvent, 10, FALSE)) {
case WAIT_OBJECT_0:
ResetEvent(hInterruptEvent);
@@ -68,23 +79,27 @@
}
}
#endif /* MS_WINDOWS */
+
if (feof(fp)) {
clearerr(fp);
return -1; /* EOF */
}
+
#ifdef EINTR
if (err == EINTR) {
- int s;
- PyEval_RestoreThread(_PyOS_ReadlineTState);
- s = PyErr_CheckSignals();
+ PyEval_RestoreThread(tstate);
+ int s = PyErr_CheckSignals();
PyEval_SaveThread();
- if (s < 0)
- return 1;
- /* try again */
+
+ if (s < 0) {
+ return 1;
+ }
+ /* try again */
continue;
}
#endif
- if (PyOS_InterruptOccurred()) {
+
+ if (_PyOS_InterruptOccurred(tstate)) {
return 1; /* Interrupt */
}
return -2; /* Error */
@@ -98,7 +113,7 @@
extern char _get_console_type(HANDLE handle);
char *
-_PyOS_WindowsConsoleReadline(HANDLE hStdIn)
+_PyOS_WindowsConsoleReadline(PyThreadState *tstate, HANDLE hStdIn)
{
static wchar_t wbuf_local[1024 * 16];
const DWORD chunk_size = 1024;
@@ -133,11 +148,12 @@
if (WaitForSingleObjectEx(hInterruptEvent, 100, FALSE)
== WAIT_OBJECT_0) {
ResetEvent(hInterruptEvent);
- PyEval_RestoreThread(_PyOS_ReadlineTState);
+ PyEval_RestoreThread(tstate);
s = PyErr_CheckSignals();
PyEval_SaveThread();
- if (s < 0)
+ if (s < 0) {
goto exit;
+ }
}
break;
}
@@ -150,17 +166,22 @@
if (wbuf == wbuf_local) {
wbuf[total_read] = '\0';
wbuf = (wchar_t*)PyMem_RawMalloc(wbuflen * sizeof(wchar_t));
- if (wbuf)
+ if (wbuf) {
wcscpy_s(wbuf, wbuflen, wbuf_local);
+ }
else {
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
goto exit;
}
}
else {
wchar_t *tmp = PyMem_RawRealloc(wbuf, wbuflen * sizeof(wchar_t));
if (tmp == NULL) {
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
goto exit;
}
wbuf = tmp;
@@ -169,33 +190,45 @@
if (wbuf[0] == '\x1a') {
buf = PyMem_RawMalloc(1);
- if (buf)
+ if (buf) {
buf[0] = '\0';
+ }
else {
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
}
goto exit;
}
- u8len = WideCharToMultiByte(CP_UTF8, 0, wbuf, total_read, NULL, 0, NULL, NULL);
+ u8len = WideCharToMultiByte(CP_UTF8, 0,
+ wbuf, total_read,
+ NULL, 0,
+ NULL, NULL);
buf = PyMem_RawMalloc(u8len + 1);
if (buf == NULL) {
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
goto exit;
}
- u8len = WideCharToMultiByte(CP_UTF8, 0, wbuf, total_read, buf, u8len, NULL, NULL);
+
+ u8len = WideCharToMultiByte(CP_UTF8, 0,
+ wbuf, total_read,
+ buf, u8len,
+ NULL, NULL);
buf[u8len] = '\0';
exit:
- if (wbuf != wbuf_local)
+ if (wbuf != wbuf_local) {
PyMem_RawFree(wbuf);
+ }
if (err) {
- PyEval_RestoreThread(_PyOS_ReadlineTState);
+ PyEval_RestoreThread(tstate);
PyErr_SetFromWindowsErr(err);
PyEval_SaveThread();
}
-
return buf;
}
@@ -209,6 +242,8 @@
{
size_t n;
char *p, *pr;
+ PyThreadState *tstate = _PyOS_ReadlineTState;
+ assert(tstate != NULL);
#ifdef MS_WINDOWS
if (!Py_LegacyWindowsStdioFlag && sys_stdin == stdin) {
@@ -230,7 +265,9 @@
if (wlen) {
wbuf = PyMem_RawMalloc(wlen * sizeof(wchar_t));
if (wbuf == NULL) {
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
return NULL;
}
wlen = MultiByteToWideChar(CP_UTF8, 0, prompt, -1,
@@ -249,7 +286,7 @@
}
}
clearerr(sys_stdin);
- return _PyOS_WindowsConsoleReadline(hStdIn);
+ return _PyOS_WindowsConsoleReadline(tstate, hStdIn);
}
}
#endif
@@ -257,16 +294,19 @@
n = 100;
p = (char *)PyMem_RawMalloc(n);
if (p == NULL) {
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
return NULL;
}
fflush(sys_stdout);
- if (prompt)
+ if (prompt) {
fprintf(stderr, "%s", prompt);
+ }
fflush(stderr);
- switch (my_fgets(p, (int)n, sys_stdin)) {
+ switch (my_fgets(tstate, p, (int)n, sys_stdin)) {
case 0: /* Normal case */
break;
case 1: /* Interrupt */
@@ -278,29 +318,40 @@
*p = '\0';
break;
}
+
n = strlen(p);
while (n > 0 && p[n-1] != '\n') {
size_t incr = n+2;
if (incr > INT_MAX) {
PyMem_RawFree(p);
+ PyEval_RestoreThread(tstate);
PyErr_SetString(PyExc_OverflowError, "input line too long");
+ PyEval_SaveThread();
return NULL;
}
+
pr = (char *)PyMem_RawRealloc(p, n + incr);
if (pr == NULL) {
PyMem_RawFree(p);
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
return NULL;
}
p = pr;
- if (my_fgets(p+n, (int)incr, sys_stdin) != 0)
+
+ if (my_fgets(tstate, p+n, (int)incr, sys_stdin) != 0) {
break;
+ }
n += strlen(p+n);
}
+
pr = (char *)PyMem_RawRealloc(p, n+1);
if (pr == NULL) {
PyMem_RawFree(p);
+ PyEval_RestoreThread(tstate);
PyErr_NoMemory();
+ PyEval_SaveThread();
return NULL;
}
return pr;
@@ -323,7 +374,8 @@
char *rv, *res;
size_t len;
- if (_PyOS_ReadlineTState == _PyThreadState_GET()) {
+ PyThreadState *tstate = _PyThreadState_GET();
+ if (_PyOS_ReadlineTState == tstate) {
PyErr_SetString(PyExc_RuntimeError,
"can't re-enter readline");
return NULL;
@@ -342,7 +394,7 @@
}
}
- _PyOS_ReadlineTState = _PyThreadState_GET();
+ _PyOS_ReadlineTState = tstate;
Py_BEGIN_ALLOW_THREADS
PyThread_acquire_lock(_PyOS_ReadlineLock, 1);